1. Technical Field
This invention relates to an apparatus to monitor movement of a computer system module. More particularly, the invention relates to a sensor for controlling power to an interface between the module and the computer system.
2. Description of the Prior Art
It has become common for computers to be serviced while performing regular functions. A typical computer includes a main board, also referred to as a “motherboard”, with a plurality of slots adapted to receive computer modules to expand the capacity and functionality of the computer. The demand for reliability in computer systems has led to the development of computer systems that support hot swapping of computer modules, including cards. This procedure allows a computer system to continue operating while a card is removed from the computer system or while a new card is inserted into the computer system. When one card is found to have a defective component or otherwise requires removal, the computer system can continue to function while the card is in the process of being removed, installed, or replaced. Accordingly, the process of hot swapping enables system components on any one of the cards to be removed, installed, or replaced without shutting down power from the computer system.
The process of hot swapping computer cards requires that power be removed from the card prior to removal from or insertion into the associated slot. One problem associated with hot swapping computer cards is the inadvertent removal of the wrong card. Given the layout of motherboards and the computer cards mounted in the associated connectors, the cards are commonly mounted close together and are often identical, or nearly identical in appearance. When the wrong card is removed, the power will not have been properly discontinued from the card prior to removal of the card from the associated connector. Removal of the computer card from the connector while the computer card is operating can have serious consequences on operation of the computer system. For example, the system is likely to continue waiting on an uncompleted process involving the inadvertently removed card. Such action can cause damage to both or either the computer card or the computer system in which the card has been operating. Accordingly, the prior art system provides the ability to hot swap computer cards without providing adequate safety measurements to ensure removal of the proper card while the system is operating.
One form of sensing movement of a computer card is shown in U.S. Pat. No. 6,138,194 to Klein et al. The '194 patent discloses a mechanical switch that is activated by a bus card when the bus card is mounted in an associated bus connector. When the card is fully inserted into the connector, the switch is in a depressed position. This positioning of the switch indicates the card is seated in the connector. When the card is removed from the connector, the switch returns to a raised position and a power switch removes power from the bus card. However, the mechanical switch is limited to a depressed position or a raised position. The Klein et al. patent does not provide a switch that detects motion of the card that may occur outside the realm of insertion or removal of the card from the connector. Accordingly, the mechanical switch in combination with the power switch does not provide the ability to remove power from the bus card during an initial movement of the card, such as movement associated with vibration.
There is therefore a need for an apparatus and method for detecting motion of a computer card and for removing power from the card experiencing the motion.